Marfan Syndrome – maybe the closest related one, marfan syndrome is a connective tissue disorder which causes skeletal defects such as long limbs, chest abnormalities, curvature of the spine and certain facial features including a highly arched palate, and crowded teeth.
Scoliosis is a deformity where the normally straight line of the spine is curved to one side, which in result deforms the ribcage. The deformity of the rib cage, as already stated can affect the regular development of the sternum and lead to the sunken chest deformity. Scoliosis is also birth anomaly, but it can develop anytime during the lifecycle of the individual, whether is from incorrect posture, pressure in the spine or physical injury. Latest studies show it affects 2% – 3% of Americans, with girls more likely to suffer from it.
A birth deformity characterized by the absence of pectoralis minor muscle and the sternum or the breastbone portion of the pectoralis major combined with abnormally short, deformed fingers on the hand. It affects males more than females and it is present mostly on the right side of the body. Doctors are still not sure about the exact reasons for this deformity.
Spinal Muscular Atrophy
Spinal muscular atrophy is also registered as one of the disorders that can lead to sunken chest. It characterises with weak intercostal muscles which affects the shape and stability of the chest wall. Because of the instability of the intercostal muscles the chest wall can appear collapsed, thus resulting in the condition pectus excavatum. It is estimated that spinal muscular atrophy is present at 1 in 6000 to 1 in 10000 births.